Ignition system.



F. CONRAD.

IGNITION SYSTEM.

APPLICATION FILED SEPT. 4. 1913. RENEWED AUG. Is. 1916.

1 ,21 9,704;- Patented Mar. 20, 1917.

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42 I /4 40 25 j A? INVENTOR M W ATTORNEY UNITED STATES PATENT OFFICE.

FBAN K CONRAD, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOB TO WESTINGHOUSE ELECTRIC AND MANUFACTUBIN G COMPANY, A CORPORATION OF PENNSYLVANIA;

' IGNITION SYSTEM.

Specification ofiLetters Patent.

Patented Mar. 20, 1917.

Application filed September-1, 1913, Serial No. 788,089. Renewed August 16, 1916. Serial No. 115,332.

To all c ham it may concern:

Be it knownthat I, FRANK Coxnao, a citizen of the'ljnited States, and a. resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Ignition Systems, of which the following is a specification.

My invention relates to ignition systems cuit, an arc follows in which the current always flows from. the same contact member to the other. The result is to cause the one contact piece to become pitted because of the surface metal being carried away and to produce projections on the surface of the other contact member because of the metal deposited during the existence of an arc. The efiiciency of the interrupter is decreased by the resulting poor electrical contact between the irregular surfaces of its contact members, and the life of the mechanism is correspondingly shortened.

It has been proposed, heretofore, to reverse the electrical connections of the interrupt-er, but such arrangements operate to reverse not only the electrical connections of the interrupter but also those of the induction coil and other elements of the ignition circuit. It has been found that such arrangements possess a number of disadvantages that are eliminated by 'a system constructed in accordance with my inven? tion.

A material disadvantage in connection with the arrangements of the prior art re-' sides in the .fact that the spark at the electrodes of a spark plug always occurs adjacent to the one or the other of the elec trodes depending upon the direction of? the currents traversing the primary and secondary circuits. The central electrode of a spark plug consists of a small rod of metal.

, spark plug.

versal of the current 'through the primary coil after each operation of the interrupter causes alternate ignition sparks to be produced adjacent to the outer electrode of the Accordingly. one-half of the sparks are of less heat intensity than the other half and uniformity of operation of the engine is not possible.

I provide a system in which the electrical connection of the interrupter contact 1118111 bers are automatically reversed after each operation. The tendency to transfer metal from one contact member to the other is thus neutralized and the result is not only to materially lengthen the life of the interrupter, but to increase its eiiiciency during operation by maintaining a substantially plane surface upon the faces of the contact members. I

The reversing switch is so arranged that the electrical connections of the interrupter only are changed, andthe current always flows in the same direction through the primary and secondary windings of the inducplugs are so connected that they constitute the negative electrodes of the air gap and,

accordingly, the ignition sparks always occur adjacent to the central electrodes. This arrangement insures that the sparks are of maximum heat value and duration.

In the dra\ vings, Figure 1 is a diagrammatic view of circuits and apparatus embodying my invention. Fig. 2 is an end view, partially in elevation and partially in section, of interrupter mechanism. Fig. 3 is a sectional view taken online III III of Fig; 2.

Referring particularly to Fig. 1, an ignition system comprises a source of current which may be either a magneto or a battery. In the present instance, a battery 1 is connected in series with the primary winding 2 of an induction coil 3 and with a resistor l which may comprise a resistor unit of nichrome wire or other suitable material.

' tem comprises the secondary winding 8 of the induction coil 3, one terminal of the winding being connected to the rotatable arm 9 of a 'distributer 10 and the other-ter- .-minal grounded as shown. The distributer frame of a magneto'or other. suitable struc-.

is provided with four contact segments-11 which are each connected to a spark plug 12.

Referring now to Figs. 2 and 3, an interrupter 13 comprises a stationary supporting member ltwhich maybe a portion of the tare. The member 14:, mprises an annular flange 15 which is provlded with a groove 1 16. The stationary portion or the interrupter comprises asleeve 17-that isrota;

tably supported within the flange l5 and is provided with two oppositely disposed cams 18. The outer end of the sleeve 17 is fitted with an insulating disk 19 which supports the contact segments 5 and 6. The segments are oppositely disposed, as diagraatically shown in Fig. l, the intervening. spaces being occupied by insulating material or suitably insulated "metal segments, as desired"; hollow conductor 20, which extends through the disk 19, is connected, at

its inner end, to the contact segment 5 by a member 21 and, at its outer end, is provided with a binding screw 22.

A cap 23, which covers the outer end of the interrupter, is provided with a flange portion '24 having a circumferential groove 25 upon its inner surface. A locking ring 26 v of resilient material occupies the grooves16 and 25 when the interrupter is assembled and provides a means for permitting relaj slit 27 which renders it sufficiently resilient, to allow the locking ring 26 to be put'in time rotative movement, but not endwise movement, between the cap 23 and the flange 15. The cap 23 is provided, with a radial place. A clamping screw 28 causes the cap 23 to retain its position relative to the flange 15 and to tightly gripthe sleeve 17. The

- ca ,23 is provided with an arm 29 to be connected in any suitable manner to the.

an inclined boss 31 for connection to the spark lever (not shown) for adjusting the time of the spark.

' The rotatable portion of the interrupter comprises a disk -which is provided with magneto shaft 32 or to any other shaft having a roper speed ratio with-the one shalt not shown). Two curved members 33 and3 i are; supported by, and insulated from, the disk 30 and respectively support a stationary contact member 35 and a lever arm 36' which carries-a contactniiember 3f? naiopoa to'coact with the contact member 35. The

,arm 36 is provided, at its free end, with a fiber bearing block 38 which engages the cams 18 in succession to rock the arm about its pivotal support indicated at 39 and against the tension'of a spring 40. The stationary contact member" 35 is electrically connected, through the curved member 33,

to an axially disposed spring-pressed brush other and oppositely disposed contact seg- 5 ment; [As the shalt 32 rotates, each brush engages'the several contact segments in succession and thus the connections are reversed twice during each revolution of the I shalt; A lthile the electrical connections, as illus trated in the diagram of Fig. 1, are indicated as being entirely metallic, 'in actual practice, the contact .jsegment 6 will be grounded to the cap 23 by means of a screw 43, Fig. 3, and one terminal of the battery and condenser will be grounded. v It may be assumed that the shaft 32 is rotating in a counter clockwise direction (Fig. 2) and that the block 38 is in a position intermediate the cams. 18 so that the contact members 35 and 3,7 are connected. lit may be assumed further that the brushes 41 and engage the contact segments 5 and6, respectively. Current then flows through the primary circuit which extends from the positive terminal of the battery 1 through the resistor 4, contact segment 5, brush 41. curved member 33, contact members 35 and circuit, and a spark occurs across the terminals of the spark plug that is connected to the distributer arm 9.

The further. rotation of the shaft 32 causes the brushes t1 and 42 to be carried out of engagementwith the respective contact seg- 37, lever arm 36, curved member 31, brush ments 5 and 6-and to engage the opposite segment: Theprimary circuit will again be closed when the block-38 moves oflthe'cam 18. Current then flows in a reversed direction between the brushes P11. and 42. When the contact members are again disengaged by the block 38 striking the next cam 18, the are which tollows between-the contact members 35 and 37 will produced by a 13 current having a direction opposite to that of the'preceding arc, and an opposite effect willfthereby be produced upon the respective interrupter contacts.

The time of the spark maybe varied by means of the arm 29 which is connected to the sparking control lever (not shown). The adjustment of the angular position of the cap 23 and the sleeve 17 causes the cams to be engaged by the block 38 at an earlier or later period in the engine stroke, accord-f ing to the direction of movement of the arm 29, I

\Vhile a condenser is employed to reduce the sparking, it is essential to employ an arrangement of the character above described to insure the eflicient operation and durability of the interrupter mechanism. The

high cost of materials, such as platinum and iridium, which are employed 1n the manufacture of contact members, render it desirable to prolong the life of these parts.

- The advantages of an ignition system which requires little. attention and few or no re-' pairs will be appreciated by those skilled in the art to which my invention appertains.

While I have shown aspec'ific form of mechanism by means of which my invention is exemplified, it is understood that the details thereof are illustrative only and not limitations, other than asdefined in the appended claims.

I claim as my invention:

1. In an ignition mechanism, the combination with a source of current, and a pair of relatively movable contact members, of means for intermittently connecting said 5 contact members in circuit with said source and means for effectmg the engagement and disengagement of said contact members whlle they are 1n circuit with said source 2. In an ignltion mechanism, the combina "tion witha source of current, and a pair of contact segments connected to the terminals, of said source, of a palr of relatively movconnected to'said contact members for enof said contact elements and said stationarv members. p 5: In an lgmtlon system, the combination .wlth 'a 0011, a source of current andan intergaging said contact segments successively,

rupter for controlling a circuit comprising said coil and said source, of a switch for reversing the connections of said source while said circuit is broken at said interrupter.

6., The combination with a source of current, an interrupter and a coil in circuit with said source and said interrupter, of means for reversing the electrical connections of said interrupter only.

7. The combination with a source of cur rent, an interrupterand a coil in circuit with said source and said interrupter, of means for periodically reversing the electrical connections of said interrupter without altering the ''connections of the remainder of the I circuit.

8. The combination with a source of current, an interrupter and a coil in circuit with said source and said interrupter,-of a reversing switch rotatable with "said interrupter for reversing the connections of the interable contact members, means forconnecting said members to sald segments successively,

and means for effecting the engagement and disengagement of said contact members while the latter are connected to said source.

3. In an ignition system, the combination with a source of current, and contact seg ments connected to the terminals of said source, a plurality of movably mounted contact members, means for controlling the relative positions of said contact members, means rupter only for each succeeding operation.

9. The combination with a source of current and .a coil, of a unitary mechanism comprising an interrupter and a reversing switch in circuit with said source and said COll, said switch 'belng operableto perlodically reverse the electrical connections of said interrupter only. Y

In testimony whereof, I have hereunto subscribed my name this'30thday of August,

- FRANK CONRAD. Witnesses:

' C. A. ATHERTON,

B. B. HI'NES. 

